1. n. [Geophysics, Geology]

Also known as weathered layer, a near-surface, possibly unconsolidated layer of low seismic velocity. The base of the weathered layer commonly coincides with the water table and a sharp increase in seismic velocity. The weathered layer typically has air-filled pores.

Alternate Form: low-velocity layer

See: pore,  static correction,  weathering,  weathering correction